mac80211: fix rx monitor filter refcounters
This patch fixes an refcounting bug. Previously it
was possible to corrupt the per-device recv. filter
and monitor management counters when:
iw dev wlanX set monitor [new flags]
was issued on an active monitor interface.
Acked-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index c981604..9e63fc2 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -68,8 +68,36 @@
params && params->use_4addr >= 0)
sdata->u.mgd.use_4addr = params->use_4addr;
- if (sdata->vif.type == NL80211_IFTYPE_MONITOR && flags)
- sdata->u.mntr_flags = *flags;
+ if (sdata->vif.type == NL80211_IFTYPE_MONITOR && flags) {
+ struct ieee80211_local *local = sdata->local;
+
+ if (ieee80211_sdata_running(sdata)) {
+ /*
+ * Prohibit MONITOR_FLAG_COOK_FRAMES to be
+ * changed while the interface is up.
+ * Else we would need to add a lot of cruft
+ * to update everything:
+ * cooked_mntrs, monitor and all fif_* counters
+ * reconfigure hardware
+ */
+ if ((*flags & MONITOR_FLAG_COOK_FRAMES) !=
+ (sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES))
+ return -EBUSY;
+
+ ieee80211_adjust_monitor_flags(sdata, -1);
+ sdata->u.mntr_flags = *flags;
+ ieee80211_adjust_monitor_flags(sdata, 1);
+
+ ieee80211_configure_filter(local);
+ } else {
+ /*
+ * Because the interface is down, ieee80211_do_stop
+ * and ieee80211_do_open take care of "everything"
+ * mentioned in the comment above.
+ */
+ sdata->u.mntr_flags = *flags;
+ }
+ }
return 0;
}